JP2906806B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing method used in a semiconductor manufacturing process for electronic devices and the like.

[0002]

2. Description of the Related Art In recent LSI technology, while dry etching is progressing due to miniaturization, an increase in current density is unavoidable in fine wiring, and the electromigration problem has become apparent. While addition of Si or Cu to aluminum is attempted to improve the reliability of wiring,
Studies have been made on u wiring.

When processing a Cu wiring, dry etching is performed using a chlorine-based gas. However, since the vapor pressure of CuClx is low, the substrate temperature is raised to 300 ° C. or higher to perform etching. In this case, since a normal photoresist mask does not have heat resistance, a mask material having high heat resistance such as an oxide film is used.

[0004]

When a chlorine-based gas is used as an etching gas, the residual chlorine reacts with moisture to cause after-corrosion (corrosion after etching), thereby causing disconnection of wiring. However, there is a problem that reliability is lowered.

An object of the present invention is to solve such a conventional problem and to provide an etching method free of after-corrosion.

[0006]

In order to achieve the above object, a method of manufacturing a semiconductor device according to the present invention comprises the steps of:
This is a method for manufacturing a semiconductor device in which a u film is finely processed by dry etching, wherein dry etching is performed using NH ₃ gas and CH ₃ OH gas.

[0007]

In dry etching of a Cu film using NH ₃ gas and CH ₃ OH gas in the present invention, Cu
A hydroxide of H ₃ OH and Cu is formed, and this Cu hydroxide utilizes the formation and elimination of a complex of NH ₃ and Cu. Accordingly, since chlorine gas is not used for the etching, the gas remaining after the etching does not react with the moisture in the air or the moisture of the cover film, and does not cause after-corrosion.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. A base oxide film 2 is formed on a Si substrate 1 shown in FIG. 1A by a thermal oxidation method or a CVD method, and a Cu film 3 is formed on the insulating film by a sputtering method or a CVD method.
Next, an oxide film 4 is formed on the Cu film 3 by a CVD method, a normal photoresist 5 is applied on the oxide film 4, and patterning is performed like a resist 5 in a normal photoresist process. .

As shown in FIG. 1B, the oxide film 4 on the Cu film 3 is patterned by dry etching with CF ₄ and CHF ₃ gases to be used as a mask material when processing the Cu film. After processing the oxide film, the resist 5 remaining on the oxide film 4 is removed by O ₂ gas plasma.

As shown in FIG. 1C, a mask oxide film 4 is formed.
Is used as a mask to perform dry etching using a mixed gas of NH ₃ gas and CH ₃ OH gas. In this case, the object to be etched is heated to 200 ° C. or more by an infrared lamp, and the ECR (E
Electron Cyclotron Resonan
ce) or RIE (Reactive Ion E)
tching) device.

For the patterning of the mask oxide film 4, an exposure process using EB (Electron Beam) may be used. In addition, in forming the mask oxide film 4,
Coating type oxide film SOG (Spin On Glass)
Alternatively, a CVD nitride film may be used. For heating the substrate during etching, heated oil may be circulated under the substrate.

[0012]

As described above, according to the dry etching of the Cu film using the NH ₃ gas and the CH ₃ OH gas in the present invention, the gas remaining after the etching is reduced by the moisture in the air and the moisture in the cover film. Since it does not react and cause after-corrosion, disconnection of wiring occurs,
Does not cause a decrease in reliability.

[Brief description of the drawings]

FIGS. 1A to 1C are cross-sectional views of a semiconductor chip for explaining one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Si substrate 2 Base oxide film 3 Cu film 4 Mask oxide film 5 Photoresist

────────────────────────────────────────────────── ─── Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) H01L 21/3213 H01L 21/3065 INSPEC (DIALOG) JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A method of manufacturing a semiconductor device in which a Cu film is finely processed by dry etching, wherein the dry etching is performed by using an NH ₃ gas and a CH ₃ OH gas. Production method.